Dumont is a Tower Guardian charged with protecting the ENCOM mainframe's I/O Tower. He resembles his user, Encom founder Walter Gibbs, and has a similar closeness with Yori that Gibbs had with her user, Lora Baines.

During Master Control's tyrannical reign, his was the last free I/O tower on the system, and bitterly remarked that he was only kept around in case one of Master Control's henchmen needed to interact by the outside world. He was nearly crippled by despair by the time Tron and Yori arrived at his tower, seeking contact with Tron's user, Alan-One. Dumont was skeptical of their odds of success, saying that he had seen "many promises, many brave plans." In the end, however, he acquiesced, allowing Tron into the sanctum to commune with his user and download the upgrade to his disc. Afterward, Dumont delayed Sark and his forces long enough for Tron and Yori to escape, sacrificing himself in the process.

Dumont was captured and tortured by Sark and Master Control, but the elderly Guardian remained defiant and remarkably sarcastic to his tormentors, taunting Sark by saying he remembered when the mighty MCP was a mere chess program, and saying that the MCP "started small and would end small." Eventually, he and many other Guardians were marched into Master Control's citadel, drained nearly to the point of de-rez. Tron rescued him and the other Guardians and Dumont stood by Tron and Yori's side at the end, overjoyed at the new freedom sweeping the system.

Trivia

He is paid homage to in TRON: Legacy, and its viral, through the shipping company called Dumont Shipping. It was named by Kevin Flynn upon taking over ENCOM and his son Sam resides in a converted Dumont shipping container, which contains a fully furnished apartment.

In the prologue for TRON: Betrayal, Dumont says that MCP was Kevin Flynn's finest creation. This is false, because MCP was created as a chess program by Dumont's user, Walter Gibbs, and was later upgraded and modified by Ed Dillinger. This would only be true if he recreated it.